The disclosed technology relates to additives that impart corrosion protection against both iron and copper corrosion to a lubricant formulation, particularly for gear lubrication or lubrication of driveline devices.
Balancing the multiple requirements of a driveline fluid presents unique challenges. Driveline lubricants, which are designed to lubricate one or more of transmissions, axles, bearings, and gears, and also contacting electronic componentry, casings or housings, and other components, must meet the requirements for lubrication of each of the components while protecting metals from corrosion and, in many instances, elastomeric seals from degradation. Alkyl amine compounds, for example, are useful as iron corrosion inhibitors in driveline applications, but they may lead to corrosion of copper-containing components.
U.S. Patent Publication 2012-0040876, Preston et al., Feb. 16, 2012, discloses anthranilic esters as additives in lubricants. This document discloses compositions that are said to deliver an ash-free base to a lubricant in the form of a basic amine additive, without adversely impacting seal compatibility.